Duo 2FA is a two-factor authentication method with Duo Security. Two-Factor authentication protects accounts against unauthorized logins by requiring a "2nd factor" in addition to a username and password. The 2nd factor is often a mobile app that is registered ahead of time or a passcode that is texted or called. With Duo 2FA, SPU accounts will be further protected against malicious logins that result from phishing attacks or other forms of cyber scams.